Coordinate input devices have an input-use panel called a tablet, and a certain position on this panel is specified by means of a pen, a mouse, etc., so that the coordinates of the specified position is inputted. Moreover, some coordinate input devices are provided with a display panel such as an LCD on the under-surface of the tablet, and the position of the inputted coordinates are displayed on the display panel.
A conventional coordinate input device having a color display means is normally provided with a color-selection means on the tablet side, which selects display colors, and selection is made from a limited number of colors displayed on the tablet by means of a pen, a mouse, etc.
Here, Japanese Laid-Open Patent Publication No. 177518/1992 (Tokukaihei 4-177518) discloses a construction wherein a switch for selecting display colors is installed on the pen side. Further, Japanese Laid-Open Patent Publication No. 115154/1996 (Tokukaihei 8-115154) discloses a construction wherein: a magnetic field having a certain intensity is generated among plurality of magnetic fields having mutually different intensities, and display is made by using a color corresponding to the intensity of the magnetic field.
However, in any of the above-mentioned arrangements, selectable colors are preliminarily set in a fixed and limited manner, and even if the user desires a half-tone color or color that is subtly different from any of the set colors, he or she has to select a color that is close to the desired color among the set colors. Therefore, these arrangements have failed to display half-tone colors or colors that are subtly different from set colors.
Moreover, in conventional arrangements, when the user tries to change a displayed color, he or she has to call for a color-setting menu onto the tablet so as to make a selection; this requires that the user has to carry out many operations by contacting the pen onto the tablet every time he or she tries to change displayed colors, resulting in a problem of complex operations.